Improvement in safety-checks for elevators



L 0 t a Y Lu LB r H0 f k 0 6 h 0 Y l e f a S No. 202,561; Patented AprilI6, 1878f WITNESSES:

N. PETERS, PHOTO-LIINOGRAPHER. WASHINGTON D, C

UNITED STATES PATENT QFFICE.

JOHN MARSHALL, OF PITTSBURG, PENNSYLVANIA,

IMPROVEMENT IN SAFETY-CHECKS FOR ELEVATORS.

Specification forming part of Letters Patent No.'202,56l, dated April16,1878; application filed November 26, 1877.

To all whom it may concern:

Be it known that I, JOHN MARSHALL, of Pittsburg, in the county ofAllegheny and State of Pennsylvania, have invented certain new anduseful Improvementsin Safety-Checks for Elevators; and I do herebydeclare the following to be a full, clear, and exact de scription of theinvention, such as will enable others skilled in the art to which itpertains to make and use it, reference being had to the accompanyingdrawings, which form part of this specification.

My invention relates to an improvement in safety-checks for elevators;and it consists in attaching a device to the ascending elevatorropes,which device, when the elevator has arrived at the desired height,checks or stops the motion of the platform by lifting the ropes from thesheaves, as will be more fully described hereinafter.

The accompanying drawings represent my invention.

Figure l is a side view of the safety-check. Fig. 2 represents the checkwhen attached to the rope. Fig. 3 shows the position of the check whenit stops the motion of the platform; Fig. 4, a front view.

The body of the check a is grooved length wise in the form of the letterV, and the bottom of the groove arched, terminating forward in astraight line. The upper edges of the body of the check are also curved,but change toward the front to straight lines I), slanting downward, andcorresponding with the inside at the bottom of the groove. At theoutside of the upper edges, and on the straight lines I), are shouldersor flanges c, notched underneath to prevent the slipping of the clamp d,which catches under and around the shoulders. In the clamp is aset-screw, Z, which serves to secure the check to the elevatorrope.

The under side of the check is an upward curve of a shorter radiusthanthat of the sheave over which the rope plays, and terminates instraight ascending lines from under the shoulders a, forming an obtuseangle, 9,

with the front. The rear end of the under side is formed by a straightline, deflecting from the curve, making an acute angle, h,

clasps and holds it.

with the line connecting the upper and lower edges, as shown in Fig. 1.p

The checks are applied to the insides of the ascending ropes, as shownin Fig. 2, so that the clamps, when secured by the screws, are outside.

The place where the clamps should be fastened is ascertained by raisingthe elevator to the desired height, and then marking the rope where itis in contact with the sheave, at which place the attachment should bemade.

When the screw is tightened upon the rope, the check assumes theposition indicated in Fig. 2, viz: the lower end of it will be at adistance from the rope, while the upper end If the elevator is nowraised to the desired height, both ends of the under side of the checkwill be in contact with the sheave, bearing against it, and the rope,which heretofore played on the sheave, lifted up and transferred to thecurved groove in the check. The rope thus held ceases to move, thefriction being transferred to the stationary check, and the elevatornecessarily stops at the desired height.

The object of my invention is to prevent the accidents frequentlyoccurring from neglect of applying the rubbers to prevent the rapidascent of the elevator when there is no counterbalancing weight tocontrol its motion.

The weights applied to facilitate the raising of heavy goods to theupper stories in warehouses is so great, that when the opposing pressureis removed from the platform before the rubbers are applied to impedethe motion of the wheels, the elevator will suddenly be raised and bemade to ascend with such velocity that when it reaches the hoistingapparatus above damage of some kind must ensue. But if the checks hereindescribed are properly applied, such accidents cannot occur, for as soonas the elevator arrives at the fixed point all motion ceases and theplatform remains stationary.

Having thus described my invention, I claim- 1. The check a, having itsinner edge shaped as shown, so as to impinge upon the sheave only at twopoints, substantially as have hereunto set my hand this 21st day ordescribed. November, 1877. 2. The check a, having a groove in its outeredge to receive the rope, and a clamping device, l, to secure it to therope at any desired Witnesses: point, substantially as set forth. T. F.LEHMANN,

In testimony that I claim the foregoing I SAML. DIESGHER.

JOHN MARSHALL.

